Heiko Stuebner authored Jul 27, 2018 and Qiang Yu committed Nov 24, 2018

A mesa driver for rockchip is defined which will call into lima when 3D
rendering is requested from it.
This uses the renderonly library from mesa, which hides the buffer
sharing details between the two drivers from the application.
This allows applications that expect a single device node like
/dev/dri/card0 (such as kmscube) to run unmodified on Rockchip devices
that use the rockchip-drm driver for display and have a Mali400 gpu using
lima.

This follows the model of the lima+sun4i drivers existing in mesa.
The code implemented here is mostly borrowed from that particular
implementation.

Rockchip socs use the same drm/kms driver throughout all socs but
multiple gpus are in use like Mali-Utgard, Mali-Midgard and also
PowerVR and Vivante.
To help with this the winsys part is set up to iterate through multiple
gpus and try each until a valid one is found. Right now of course only
the Lima-supported GPUs are implemented but it can be easily adapted
for the other ones, once Mesa drivers are available for them.

Signed-off-by: Heiko Stuebner <heiko@sntech.de>